Ignition system



Oct. 24, 1950 so 2,527,211

IGNITION SYSTEM Filed July 9, 1943 IN V EN TOR.

BY d 5mm, 5. Mwm/ MM A TTOP/VFY Patented Oct. 24, 1950 IGNITION SYSTEMHarry A. Brinson, Sidney, N. Y., assignor to Ben dix AviationCorporation, New York, N. Y., a corporation of Delaware Application July9, 1943, Serial No. 494,113

3 Claims.

This invention relates to electrical apparatus and more particularly toignition means for internal combustion engines and the like.

One of the objects of the present invention is to provide novel boosterignition means adapted for use with either a low or high tensiondistribution ignition system for an internal combustion engine.

Another object of the invention is to provide novel means for supplyinghigh voltage current to the spark plugs of an engine for creating sparksin the engine cylinders at predetermined times in timed relation withthe operation of other parts of the engine;

Another object is to provide novel ignition means which are operableindependently of the speed of the engine whereby starting of the engineis facilitated. 7

Still another object is to provide a novel method for'creating sparksacross a gap, such as across the points of a spark plug in the cylinderof an internal combustion engine.

A further object is to provide a novel booster ignition system adaptedfor use in starting internal combustion engines which are normallyoperated by a magneto-generator or similar current generating means.

The above and further objects and novel features of the invention willmore fully appear from the following detailed description when the sameis read in connection with the accompanying drawings. It is to beexpressly understood, however, that the drawings are for the purpose ofillustration only and are not intended to define the limits of theinvention, reference'for this latter purpose being primarily had to theappended claims. In the drawings, wherein like reference charactersrefer to like parts throughout the several views,

Fig. 1 is a diagrammatic view illustrating one form of high tensiondistribution ignition system embodying the present invention; and,

I Fig. 2 is a diagrammatic view illustrating one form of low tensiondistribution ignition system embodying the invention.

" In the embodiment of Fig. 1, the invention is illustrated by way ofexample in the form of an ignition system for a 9-cylinder enginewherein the electrical energy for normal operation of the engine isgenerated by a magneto-generator or the like and is distributed to thespark plugs of an engine at relatively .high voltage. Any of manywell-known types of magnetos may he employed for carrying out theinvention "in this .means (not shown) capacity used in standardproximately .25 microfarad.

form, the magneto shown being of the type which consists of a 4-polemagnetic rotor 5 adapted to be driven in any suitable manner by theengine and a 2-pole stator 6 adapted to cooperate with rotor 5 .in amanner well understood in the art. Wound on stator 6,is an ignition coilconsisting of a primary or low tension winding 1 and a secondary or hightension winding 8, said coils having the electrical characteristics ofastandard magneto.

One end of primary winding 1 is preferably grounded at'9 and there is acircuit breaker consisting of a movable point or contact I0 andstationary point or contact ll connected across it in the usualwell-known manner to form a primary or low voltagecircuit. The points ofthe circuit breaker H], II are normally biased to engaged or closedposition either by the resiliency of movable arm IZ or by other suitableresilient A rotatable cam [3 or any other suitable known means may beprovided for periodically separating the points of circuit breaker Ill,ll to thereby interrupt the circuit through primary winding 1. Cam l3may be driven by the engine in timed relation with rotor 5. In order toeliminate or minimize arcing at points IO, U, when the same areseparated by cam l3, a condenser l4 may be connected across said points.This condenser is preferably of the magnetos, i. e., ap-

One'end of secondary winding 8 is preferably connected to the groundedor low potential end of primary winding 7, and the other end of saidsecondary winding is connected by lead I5'to the input terminal N5 of ahigh tension ignition distributor ll. High tension current flowingthrough lead l5 from secondary winding 8 is picked up by the rotatingarm l8 of the distributor and delivered in a manner well-known in theart to the circularly arranged output terminals IQ of the distributorwhich are in turn connected by leads 2!] to spark plugs 2| in. thecylinders of an engine. One terminal of each spark plug is grounded inany suitable manner, as at 22.

The ignition system thus far described is of the character heretoforeuniversally employed for hightension distribution of the currentgenerated by the magneto. In the operation thereof, the rotation ofrotor 5 induces alternating current at relatively low voltage in theprimary circuit which includes winding 1' and circuit breaker l0, ll. Ator about each time the induced current in the primary circuit reachesits maximum value, said circuit is interrupted by the separawinding 8.

3 tion of circuit breaker points in and H and the resulting suddendecrease in the electric current flowing in winding 1 and, hence, thesudden collapse of the magnetic field about windings 1 and 8 induces acurrent at high voltage in secondary Rotor 5, cam I3 and distributor iiiare preferably all driven by the engine in timed relation to one anotherso that the high voltage current thus induced in the secondary circuitwill flow from winding 8 through lead and distributor arm 18 to one ofthe distributor terminals l9 and thence to a spark plug 2| for creatingan arc across the gap thereof. The combustible charges in the enginecylinders will thus be ignited in a predetermined sequence as is wellunderstood in the art.

When starting an engine on which the above system is installed, thestarting motor (not shown) does not ordinarily rotate the enginecrankshaft and, hence rotor 5 at a sufficiently high speed to generateenough energy to create the necessary sparks at the spark plugs in theengine cylinders. Accordingly, for the purpose of starting the engine, aso-called booster source of electrical energy, such as a battery 23, maybe employed. A battery having a rated voltage of '24 volts is ordinarilysufficient. The present 1 ntion contemplates novel means fo utilizingthe'ene'rgy of battery 23 in a novel manner in conjunction with theignition system heretofore discussed'to provide the necessary energy forstarting the engine. In the form shown, one terminal of the battery isconnected to ground at 24 and the other terminal thereof is connectedthrough a switch 25 to one end of a coil 26 which, together with ametallic core 21 on which it' is wound, constitutes an electro magnetfor opera 'ng a pair of buzzer contacts 28, 29 in a manner to be morefully described hereafter. Switch 25 may be manually operable andnormally biased to open position by any suitable means, such as aspring, or it may be an automatic switch adapted to be mechanically ormagnetically opened whenever the engine is operating ata sufficientlyhigh speed to insure the genelectrical energy by magneto 5, 6. Theotherend of coil 26 is connected by means of a lead 30 to buzzer contact 28,which is mounted on a pivoted arm 3! and is normally biased intoengagement with contact 29 by a spring 32 or other suitable resilientmeans. Buzzer contact 29 is connected by means of a lead 33 to circuitbreaker contact II and the ungrounded end of primary winding 1. Acondenser 34 which preferably has a capacity of approximately .25microfarad is connected in shunt with buzzer contacts 28, 29 to reducearcing between the same. I

Inorder to reduce the amount of current which flows through coil 26 forpurposes to hereinafter appear and for other reasons which will appearhereinafter, a resistance 35, which preferably has a value of from 8 to12 ohms (approximately), is connected in shunt with said coil. The ohmicvalue of resistance 35 and the physical and electrical characteristicsof the buzzer breaker parts 28, 29, 3!, 32 and electro-magnet 26, 21 foroperating said breaker are preferably :such that points 28, 29 will beelectromagnetically separated whenever the current flowing in lead 33reaches a value of from 7 to 9 amperes. Tl'le'inductance of coil 25 ispreferably no more than 3 to 4 millihenries and the overall distribedresistance of lead 33 should be kept below approximately one ohm in mostinstallations.

eration of adequate For the purpose of rendering the ignition sys-- teminoperative and, hence, prevent operation of the engine on which thesame is mounted, a suitable ignition switch 36 may be provided forgrounding the high potential end of primary winding 1, as at 31. Thus,when switch 36 is in closed position, both ends of primary winding 1will be connected to ground and thereby render circuit breaker 10, Hincapable of interrupting any flow of current through said winding.Also, when switch 36 is in closed position, very little, if any, currentwill flow from battery 23 to winding 1 when switch 25 is also in closedposition.

When it is desired to start the engine, the starting or booster circuitmay be rendered operative by closing switch 25 when ignition switch 36is in open position, it being understood that the closing of switch 25may be effected by closing the circuit to a starting motor (not shown)which is operative to slowly turn the crankshaft of the engine on whichthe ignition system is installed. Current will then flow from battery 23through coil 26' and resistance 35. Since the only function ofelectro-magnet 26, 21 is to separate points 28, 29, only a small portionof the current from the battery need flow therethrough, From theconnected ends of coil 26 and resistance 35, the current flows throughcontacts 28, 29 into lead 33. When circuit breaker contacts H], H are inclosed position, the current flows from lead 33 across said contacts toground at 9. Whenever this current reaches a predetermined value in thevicinity of approximately '1 to 9 amperes, electro-magnet 26, 21 becomeseffective to separate contacts 28, 29, thereby breaking the circuitthrough coil 26 and deenergizing the electro-magnet. Contact points 28and 29 are then closed again by spring 32 andthe cycle of operation isrepeated in rapid succession. By reason of the resistance 35 and itsability to dissipate electrical energy, arcing across points 28, 29 whenthe same are separated is substantially eliminated and, in addition,this resistance absorbs the inductive kick, so to speak, which resultsfrom the self-induction of coil 26 when the current therein dropssuddenly upon the opening of contacts 28, 29.

As pointed out above, the interrupted current from the booster mechanismflows to ground at 9 whenever circuit breaker contacts [0 and II are inclosed position. When the latter contacts are moved to open position, i.e., at the instant a spark is desired in an engine cylinder, theinterrupted booster current is directed through primary Windin 1. Theflow of this interrupted current through the primary winding generates ahigh voltage interrupted current in secondary windin 8, which current isdistributed to spark plugs 2i in the manner fully set out above. Whenthe engine begins to run sufficiently fast, switch 25 may be released orautomatically opened and the required energy for firing the spark plugswill be supplied by magneto 5, 6 in the manner heretofore described.

In the second embodiment of the invention illustrated in Fig. v2, thefeatures of the invention are shown, by way of example, as beingembodied in an ignition system for a 9-cylinder engine wherein theelectrical current is distributed at relatively low voltage, the voltagebeing stepped up at a transformer or spark coil near each spark plug forthe purpose of creating the necessary ignition spark across the pointsof the plug. In the form shown, the main ignition current for normalengine operation is generated by a magneto which comprises a magnetowhich embodies a magneto rotor 46 adapted to cooperate with stator poles41 that are, in turn, connected by a core 48 on which a coil 49 iswound. Upon rotation of rotor 46, such as by the engine, alternatingcurrent at relatively low voltage is generated in coil 49 in a mannerwell understood in the art. The electrical characteristics of coil 49will depend upon the particular engine on which the ignition system isutilized and may be readily determined by anyone skilled in the art. There sistance of the coil should probably be quite low, a coil having aresistance of one-tenth of an ohm having been found satisfactory in onesuitable embodiment.

One end of coil 49 is preferably grounded, as at 44, and the other endthereof is connected by a lead 59 to one contact of a circuit breaker5!, the other contact of which is also grounded at 44 or otherwise. Thecontacts of circuit breaker 51! are normally urged to engaged or closedposition by suitable resilient means (not shown) and are periodicallymoved out of engagement .with each other or to open position, as shown,by a rotatable cam52 which may also be driven by the engine in timedrelation with rotor 46. Cam 52 may be of any suitable design but if theignition system is used on a radial engine the cam is preferably of thecompensated type having a lobe for each cylinder of the engine, saidlobes being spaced to properly time the sparks in each cylinder. Acondenser 53 is preferably connected across the terminals of circuitbreaker 5? to reduce arcing when the contacts are separated.

The insulated or ungrounded terminal of circuit breaker 5i is connectedto a suitable distributor D, which ma take the form of any of manywell-known designs. In the illustrated embodiment, the distributorcomprises a stationary insulated metallic ring 54 to which circuitbreaker 5| is connected by means of a lead 55 and a plurality ofarcuatecircularly arranged insulated contacts 56. Current delivered toring 54 from magneto 45 or other suitable source through leads 56 and 55is picked up by a carbon or similar brush 5! carried by rotating distributor finger 58 and conducted to contacts 56 through a brush 59 whichis also carried by said finger and electrically connected with brush 51by a conductor 69. Distributor finger 58 may be rotated by the engine intimed relation with cam 52 and magneto rotor 46. 7

Each of the distributor contacts 56 is connected by means of a lead 6|to the primary winding 62 of a spark coil, which winding is in turnconnected to ground at 63. By controlling the flow of electrical currentat relatively low voltage to coil winding 62, in the manner to behereinafter described, a high tension current is induced in secondarywinding 64 of the spark or ignition coil and creates a spark across thepoints of a spark plug 65 in the cylinder of the engine.

When it is desired to stop operation of the engine in which theabove-described ignition system is installed, the ungrounded end ofmagneto coil 49 may be connected to ground through an ignition switch65, one terminal of which is connected by a lead 61 to said coil. Theother terminal of said switch may be grounded at 69 in any suitablemanner.

In the operation of the ignition. system thus far described withignition switch 66 in open position, the contacts of circuit breaker 5|are held in closed position during the time that current is being builtup in coil 49 of the magneto generator. Each time the current in coil 49approaches its maximum value, the points of circuit breaker 5| areopened by one of the lobes on rotating cam 52, whereupon the currentfrom the coil must flow through leads 56 and 55 and distributor D in themanner fully described above to an ignition coil primary winding 62.This sudden surge of current, which results primarily from theself-inductance of coil 49, flows through winding 62 and is efiective toinduce the necessary energy in the secondary circuit, which includessecondary winding 64, to create a spark across the spark plug gap at 65in the engine cylinder. As distributor finger 58 moves brush 59 over thecontacts 56, the spark plugs of the engine are successively fired in apredetermined sequence, the timing of each spark being determined'by theopening of circuit breaker 5 I.

In an ignition system of the above character, it is highly desirable toprovide an electrical resistance in the primary or low voltage circuit.which is of sufficient magnitude to quickly dissipate the residualenergy in said circuit after the occurrence of each spark at a sparkplug. This dissipation of the residual energy is desirable in order toprevent arcing at the distributor contacts and to obviate thepossibility of secondary sparks at the spark plugs when distributorbrush 59 moves from one contact 56 of the distributor to another suchcontact. The desired resistance is preferably incorporated in theprimary windings 62 of the transformer coils, thereby making it possibleto use smaller wire and reduce the size of these coils to a minimum. Inone satisfactory embodiment of the invention, resistance of 16 ohms ineach primary winding- 62 and the leads connected with it has been foundto be suitable. This resistance value may differ, however, withdifferent installations.the.

most suitable value may be determined by resorting to oscillograph orlike measuring means for determining the characteristics of the currentin the primary circuit during operation of the engine. The resistancemay be incorporated in the primary circuit at any desired point or maybe distributed in the leads and should only be sufficiently large toproduce the desired dissipation of the residual energy within a suitableinterval to'accomplish the above-mentioned results.

Since rotor 45 is driven by the engine, sufficient electrical energycannot be generated by magneto 45 to efiect the necessary sparks at thespark plugs when the crankshaft of the engine is turned slowly by astarting motor. Accordingly, for use in starting the engine a boosterwhich is identical with the booster shown in Fig. 1 may be provided forcooperation in a novel manner with the main ignition circuit of Fig. 2described above. The output lead 33 of the booster unit or circuit is,in this event, connected to lead 56, 55 of the main circuit. Thisconnection is preferably made at a point such that a substantialportion, preferably substantially all of the resistance of each circuitinvolving a primary winding 62, will be on the same side of saidconnecting point as said primary winding-the resistance from saidconnecting point through magneto coil 49 or circuit breaker 5! should berelatively very low.

The booster unit per se of Fig. 2 operates as a buzzer or currentinterrupter in the same manner as described above in connection withFig. 1

by cooperation with the main or low tension distribution ignitioncircuit in a somewhat difierent manner. With switch 66 open and switch25 closed, contacts 28, 29 are opened and closed in rapid succession byelectro-magnet 26, 21 and spring 32, thereby interrupting the flow ofcurrent from battery 23 to the main ignition circuit. Because of thehigh resistance in the circuit through the distributor and a primarywinding 62, as heretofore explained, substantially all of the boostercurrent will flow from lead 33 into lead 50 and thence through circuitbreaker or coil 49, depending on whether said circuit breaker is closedor open. The timing of the initial spark in each cylinder of the engineis accordingly efiected during the starting operation by circuit breaker5| in the same manner that the sparks are timed during normal operationof the engine.

With circuit breaker 5| in open position, current from the booster unitbuilds up at a relatively slow rate in coil 49 to a suitable value- '7to 9 amperes having been found sufiiicient for one operativeembodimentwhile contacts 28, 29 are engaged and tends to drop offsuddenly to zeroamperes when the latter contacts are separated tointerrupt thev flow of current from the battery. The current decrease incoil 49 and the resulting collapse of themagnetic field about said coilcauses a sudden surge of self-induced current through the only availablecircuit, i. e.,

through the primary winding 62, which is at that moment connected withsaid coil through distributor D. This sudden surge or increase ofcurrent flow through winding 62 is effective to induce a high voltagecurrent in the associated secondary winding 64 and, hence, cause a sparkat the gap of spark plug 65. Since the contacts 28, 29 may open andclose several times during each interval that circuit breaker 5| is heldin open position by rotating cam 52, a veritable shower of sparks mayoccur at each spark plug and thereby facilitate starting of the engine.

When the engine starts, i. e., when rotor 46 is turned sufficiently fastby the engine to produce the required current for operating the enginewithout the assistance of the booster coil unit, starter switch 25 maybe opened automatically or otherwise by any of many suitable meanswell-known in the art. Any operation of the booster coil unit or anyinterference thereof with the normal operation of the engine will thusbe prevented during such normal operation.

There is thus provided an ignition system wherein novel, simplifiedmeans for supplying the starting energy for an internal combustionengine in combination with a magneto generator and circuit breaker meanswhich are employed for supplying and controlling the eelctrical energyfor normal operation of the engine are provided. A novel boosterignition means is provided for engine starting purposes, which systemutilizes the circuit breaker of the main ignition system for timingpurposes and is adapted for use in combination with either high tensiondistribution or low tension distribution ignition systerns.Additionally, the novel booster unit contemplated by the invention maybe connected into the main ignition circuit by means of a relativelysmall amount of wiring and, hence, weight, cost, upkeep andpossibilities of failures are reduced to a minimum. Additionally, thenovel booster system provided is operable equally well at' all altitudesirrespective of the pressure Variations.

Although or two er. tion are illustrated in diagrammatic form. and

a l ents of theinvene described in the foregoing specification, it isexpressly understood that various changes may be made therein withoutdeparting from the spirit and scope of the invention as the same willnow be understood by those skilled in the art. For example, the boostercoil unit may be connected into the main ignition circuit at pointsother than those illustrated and the various units of the ignitionsystem, such as the magneto and distributor, may assume different formsthan those illustrated. The number of cylinders or spark plugs may bevaried and the values of the resistances, inductances, capacities, etc.,which have been mentioned by way of example, may be varied in ignitionsystems for engines of difierent sizes and horsepower ratings. For adefinition of the limits of the invention, reference is had primarily tothe appended claims.

What is claimed is:

1. In ignition apparatus, a source of uni-directional electricalcurrent, an electrical resistor connected at one end to one terminal ofsaid source, a circuit breaker having one contact thereof connected tothe other end of said resistor, resilient means for normally holding thecontacts of said circuit breaker in engagement, means including a coilconnected in parallel with said resistor {or electromagnetically openingsaid circuit breaker, an induction coil, a transformer coil having aprimary winding, means connecting one end of said induction coil to oneend of said primary winding, means, such as a common ground, forconnecting the other ends of said induction coil and primary winding andthe other terminal of said source, means connecting the other contact ofsaid circuit breaker to said first named connecting means for saidinduction coil and primary winding, the resistance to current fiowthrough said primary winding being many times greater than theresistance to current flow through said induction coil, a secondnormally closed circuit breaker connected in parallel with saidinduction coil for diverting current from said source around saidinduction coil, and means for periodically opening said second circuitbreaker.

2. In ignition apparatus, a source of uni-directional electricalcurrent, an electrical resistor connected at one end to one terminal ofsaid source, a circuit breaker having one contact thereof connected tothe other end of said resistor, resilient means for normally holding thecontacts of said circuit breaker in engagement,

means including a coil connected in parallel.

with said resistor for electromagnetically opening said circuit breaker,an induction coil, a transformer coil having a primary winding, meansconnecting one end of said induction coil to one end of said primarywinding, means, such as a common ground, for connecting the other endsof said induction coil and primary winding and the other terminal ofsaid source, means connecting the other contact of said circuit breakerto said first-named connecting means for said induction coil and primarywinding, the resistance'to current flow through said primary windingbeing many times greater than the resistance to current flow throughsaid induction coil, a second normally closed circuit breaker connectedin parallel with said induction ccil for diverting current from saidsource around said induction coil, means for periodically opening saidsecond circuit breaker, and means including a permanent magnet and arotatable element for inducing alternating current in said inductioncoil when said element is rotated.

3. In an internal combustion ignition system comprising a magneto havinga coil with one end thereof connected to ground, means for inducingalternating current in said coil, a periodically operable circuitbreaker connected across said coil and a transformer coil having theungrounded end of the primary Winding thereof connected to theungrounded end of said coil, the combination therewith of a booster unitincluding a source of unidirectional electrical current, a secondnormally closed circuit breaker, an electrical resistor connectedbetween one contact of said second circuit breaker and the ungroundedterminal of said source, electromagnetic means including a coilconnected in parallel with said resistor for electromagnetically openingsaid second circuit breaker, the ohmic resistance of said resistor beingmany times greater than the ohmic resistance of said last-named coil,and means connecting the other contact of said second circuit breaker tothe connection between the ungrounded ends of said magneto coil and saidprimary winding, the resistance to flow 10 of electrical current throughsaid primary winding being many times greater than the resistance toflow of electrical current through said magneto coil.

HARRY A. BRINSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

